My database is only using 2 online undo file groups, both 1 file, 5M.
Then I
CREATE TABLE(col char(2000));

Now I insert 1000 rows, a 20M size transaction.
I see the log archive process copying files to the archive destination.

Here is my question: I can both commit and rollback the transaction. There is no error generated.
But to my knowledge, the transaction should be able to fit into the online log, ie, 10M or less. How does oracle commit or rollback this larger transaction?

I also tried removing the archived logs before commit or rollback, every thing is ok, I can do both. It seems oracle does use archived log.

hello mr or mrs :
excuse me i think you don't know what are redo log files doing actually.
commit and rollback do not use online and archive files for rollback and commit transactions .
if you are working in oracle 9i we have two way for rollback transaction auto and manual;
in manual we use rollback segment and in auto we use rollback tablespace that is better way and easilly.
this is not correct 'the transaction should be able to fit into the online log '
for example you can insert two recored then do switch log file then
insert two recored then do switch log file then
insert two recored then do switch log file
and ... without any problem and in the end do commit or roolback because
oracle does not use and does not change that online and archive file
we use these files for recovery .